Only show compatibility date fallback warning if new version available

packages/wrangler/src/dev.tsx

@@ -346,7 +346,7 @@ export async function startDev(args: StartDevOptions) {
 		if (args.logLevel) {
 			logger.loggerLevel = args.logLevel;
 		}
-		await printWranglerBanner();
+		const maybeNewVersion = await printWranglerBanner();
 		if (args.local) {
 			logger.warn(
 				"--local is no longer required and will be removed in a future version.\n`wrangler dev` now uses the local Cloudflare Workers runtime by default. 🎉"
@@ -471,6 +471,7 @@ export async function startDev(args: StartDevOptions) {
 					firstPartyWorker={configParam.first_party_worker}
 					sendMetrics={configParam.send_metrics}
 					testScheduled={args.testScheduled}
+					newVersion={maybeNewVersion}
 				/>
 			);
 		}
@@ -611,6 +612,8 @@ export async function startApiDev(args: StartDevOptions) {
 			sendMetrics: configParam.send_metrics,
 			testScheduled: args.testScheduled,
 			disableDevRegistry: args.disableDevRegistry ?? false,
+			// `unstable_dev()` doesn't perform an update check
+			newVersion: undefined,
 		});
 	}
 

packages/wrangler/src/dev/dev.tsx

@@ -164,6 +164,7 @@ export type DevProps = {
 	firstPartyWorker: boolean | undefined;
 	sendMetrics: boolean | undefined;
 	testScheduled: boolean | undefined;
+	newVersion: string | undefined;
 };
 
 export function DevImplementation(props: DevProps): JSX.Element {
@@ -344,6 +345,7 @@ function DevSession(props: DevSessionProps) {
 			onReady={announceAndOnReady}
 			enablePagesAssetsServiceBinding={props.enablePagesAssetsServiceBinding}
 			sourceMapPath={bundle?.sourceMapPath}
+			newVersion={props.newVersion}
 		/>
 	) : (
 		<Remote

packages/wrangler/src/dev/local.tsx

@@ -41,6 +41,7 @@ export interface LocalProps {
 	enablePagesAssetsServiceBinding?: EnablePagesAssetsServiceBindingOptions;
 	testScheduled?: boolean;
 	sourceMapPath: string | undefined;
+	newVersion: string | undefined;
 }
 
 // TODO(soon): we should be able to remove this function when we fully migrate
@@ -173,7 +174,7 @@ function useLocalWorker(props: LocalProps) {
 		let server = miniflareServerRef.current;
 		if (server === undefined) {
 			logger.log(chalk.dim("⎔ Starting local server..."));
-			const newServer = new MiniflareServer();
+			const newServer = new MiniflareServer(props.newVersion);
 			miniflareServerRef.current = server = newServer;
 			server.addEventListener("reloaded", async (event) => {
 				await maybeRegisterLocalWorker(event, props.name);

packages/wrangler/src/dev/miniflare.ts

@@ -112,6 +112,10 @@ export interface ConfigBundle {
 }
 
 class WranglerLog extends Log {
+	constructor(logLevel: LogLevel, private readonly newVersion?: string) {
+		super(logLevel);
+	}
+
 	#warnedCompatibilityDateFallback = false;
 
 	info(message: string) {
@@ -122,10 +126,18 @@ class WranglerLog extends Log {
 
 	warn(message: string) {
 		// Only log warning about requesting a compatibility date after the workerd
-		// binary's version once
-		if (message.startsWith("The latest compatibility date supported by")) {
+		// binary's version once, and only if there's an update available.
+		if (
+			this.newVersion !== undefined &&
+			message.startsWith("The latest compatibility date supported by")
+		) {
 			if (this.#warnedCompatibilityDateFallback) return;
 			this.#warnedCompatibilityDateFallback = true;
+			message += [
+				"",
+				"Features enabled by your requested compatibility date may not be available.",
+				`Upgrade to \`wrangler@${this.newVersion}\` to remove this warning.`,
+			].join("\n");
 		}
 		super.warn(message);
 	}
@@ -139,11 +151,13 @@ function getIdentifier(name: string) {
 	return name.replace(IDENTIFIER_UNSAFE_REGEXP, "_");
 }
 
-function buildLog(): Log {
+function buildLog(newVersion: string | undefined): Log {
 	let level = logger.loggerLevel.toUpperCase() as Uppercase<LoggerLevel>;
 	if (level === "LOG") level = "INFO";
 	const logLevel = LogLevel[level];
-	return logLevel === LogLevel.NONE ? new NoOpLog() : new WranglerLog(logLevel);
+	return logLevel === LogLevel.NONE
+		? new NoOpLog()
+		: new WranglerLog(logLevel, newVersion);
 }
 
 async function buildSourceOptions(
@@ -459,9 +473,14 @@ export type MiniflareServerEventMap = {
 	error: ErrorEvent;
 };
 export class MiniflareServer extends TypedEventTarget<MiniflareServerEventMap> {
-	#log = buildLog();
+	readonly #log: Log;
 	#mf?: Miniflare;
 
+	constructor(newVersion: string | undefined) {
+		super();
+		this.#log = buildLog(newVersion);
+	}
+
 	// `buildMiniflareOptions()` is asynchronous, meaning if multiple bundle
 	// updates were submitted, the second may apply before the first. Therefore,
 	// wrap updates in a mutex, so they're always applied in invocation order.

packages/wrangler/src/dev/start-server.ts

@@ -133,6 +133,7 @@ export async function startDevServer(
 			usageModel: props.usageModel,
 			workerDefinitions,
 			sourceMapPath: bundle?.sourceMapPath,
+			newVersion: props.newVersion,
 		});
 
 		return {
@@ -318,7 +319,7 @@ export async function startLocalServer(props: LocalProps) {
 
 	const config = await localPropsToConfigBundle(props);
 	return new Promise<{ stop: () => void }>((resolve, reject) => {
-		const server = new MiniflareServer();
+		const server = new MiniflareServer(props.newVersion);
 		server.addEventListener("reloaded", async (event) => {
 			await maybeRegisterLocalWorker(event, props.name);
 			props.onReady?.(event.url.hostname, parseInt(event.url.port));

packages/wrangler/src/index.ts

@@ -96,7 +96,12 @@ ${TOML.stringify({ rules: config.build.upload.rules })}`
 	return rules;
 }
 
-export async function printWranglerBanner() {
+/**
+ * Prints the current version of Wrangler, checking for updates and printing
+ * the new version if available. Returns the new version number if an update
+ * is available, or `undefined` otherwise.
+ */
+export async function printWranglerBanner(): Promise<string | undefined> {
 	// Let's not print this in tests
 	if (typeof jest !== "undefined") {
 		return;
@@ -129,6 +134,8 @@ After installation, run Wrangler with \`npx wrangler\`.`
 			);
 		}
 	}
+
+	return maybeNewVersion;
 }
 
 export function isLegacyEnv(config: Config): boolean {